The Anatomy of the Muscular System

The Functions of The Muscular System

Movement and Support:The more than 600 muscles in the human body all play vital roles in maintaining a good posture and actually being able to move. The nervous system sends signals to the muscles that tell the fibers to begin sliding. These sliding fibers cause contractions that, when working together, for basic muscle motion. These muscles help us hold ourselves up and also to have the mobility necessary to function.

Temperature Regulation: The muscular system can assist in both the heating and cooling process of the body. In the heat, these muscles allow for sweat to be excreted through the skin. In extreme cold, the muscles attempt to warm the body by contracting quickly, which translates to shivering. This muscle movement generates heat that is used to keep the body warm.

Digestion: After your jaw muscles allow you to chew your food, a series of involuntary muscle movements help to carry this food through the digestive tract. In the stomach, the muscles help to churn the food, which aides in further nutrient and energy absorption.

Circulation: The muscles that never rests and keeps virtually every part of the body functioning is the heart. This organ made of cardiac muscle is constantly contracting to push blood through. The arteries also have this cardiac muscle to pump the blood to all areas of the body.

The Three Types of Muscle

Skeletal Muscle

Often called striated muscle, skeletal muscle is part of what comprises the musculoskeletal system, which connects muscles and bones for voluntary body movements. Skeletal muscle is attache to both ends of a bone by the tendons. When its myofibers slide in and out, the muscle contracts to generate movement.

Smooth Muscle

Smooth Muscle is found in many of the organs of the body, such as the esophagus and stomach. These kinds of muscles are involved in involuntary motion, for example the smooth muscle of the eyes helps them focus without the prompt of the nervous system. Smooth muscle has no striations and has cells that are described as spindle shaped.

Cardiac Muscle

Cardiac muscle makes up the thick, inner myocardium layer of the heart. This strong muscle is what enables the heart muscle to pump continuously and involuntarily without ever resting. Cardiac muscle can also be found in some arteries. This kind of muscle promotes the circulation necessary to sustain the entire body.

Muscle Movement

These images above display the process by which the fibers in skeletal muscle, with the fuel of Adenosine Triphosphate (ATP), slide to generation muscle movement. This process is often referred to as the "sliding filament theorem". These images display the movement of just one pair, but when thousands of these join together at the signal of the nervous system, they work in unison to quickly and efficiently move the body.

At rest, the actin and myosin proteins are prevented from interacting by Tropomyosin, which binds to the actin until movement is necessary, in which the Ca ions will upset the balance and allow for interaction.

ATP gives up a phosphate ion to become ADP. This gives myosin the ability to bind to actin, which causes it to stretch out. When the phosphate is replenished, the ATP allows the myosin to repeat this process.